The University of Iowa, in conjunction with the Environmental Protection Agency's State Radon Survey Assistance Program, performed a 222Rn screening survey of 582 rural households in the winter of 1989. The distribution of maximum indoor 222Rn concentrations throughout Iowa as well as the relationship between 222Rn screening measurements, detector placement, and housing characteristics are summarized. This report is unique in that site-specific home construction characteristics were collected in the field from participants prior to 222Rn monitoring. The findings of the survey indicate that the significance of a particular housing characteristic on a 222Rn screening measurement is dependent on the placement of the radon detector.